When a flashlight is dropped, the resulting abrupt impact with a hard surface can damage both the external and internal parts of the flashlight. That is, the impulse applied to a flashlight upon impact can break the lens, light source, light switch and casing, as well as damage the batteries and internal electrical circuits. While some flashlights have been provided with resilient covers, none is known to be able to withstand the impact from a fall of up to 100 feet.
This disclosure is directed to a shock absorbing system for a flashlight and to a flashlight fitted with the shock absorbing system that can withstand the impact from a fall of up to 100 feet. Potentially damaging impacts are absorbed from all directions with a shock absorbing system that includes an external shock absorber on both the head or front portion of a flashlight and on the tail or rear portion of a flashlight. Each external shock absorber includes a series of axially-extending flexible fins which are designed to resiliently flex and bend upon impact so as to reduce impact impulses and provide a more gradual deceleration of the flashlight. The flexing and bending of the fins dampens the impact by providing a predetermined distance over which the fins can deform while absorbing, distributing and dissipating the kinetic energy of a falling flashlight.
This absorption of energy by resilient deformation of the fins can be augmented with the provision of an optional axial and radial clearance zone around each end of a flashlight. These open clearance spaces allow for additional deflection of the fins and provide a space through which impacts and impulse forces are absorbed by additional resilient deformation of a series of circumferentially-spaced-apart fins. In effect, an annular “safety zone” or “crumple zone” is formed around the front crown of a flashlight as well as around the rear tail cap of a flashlight. That is, in one embodiment, before any contact occurs between the fins and the flashlight, the fins resiliently deflect over a predetermined distance so as to absorb shock forces. In this manner, reduced shock forces are transferred to the flashlight.
Additional shock absorbing protection is provided on both the front and rear shock absorbers in the form of axially-extending resilient ribs which protrude radially outwardly away from the body of a flashlight. In this manner, the ribs make first contact with any impact surface before any contact is made against the underlying flashlight body or casing. In one embodiment, the ribs can extend axially into each respective fin so as to provide supplemental support to each fin and to further distribute impact forces over a larger surface area around the flashlight casing.
In the case of the front shock absorber, the bottom of the fins are formed with radially-inwardly extending engagement surfaces which overlie the leading circular edge of the flashlight crown. The engagement surfaces can be homogeneously molded with a front annular flange having a bottom wall axially spaced over the edge of the flashlight crown. In this manner, impact forces are first absorbed by deformation of the fins and then reduced forces are distributed circumferentially around the flashlight crown by the front annular flange and a cylindrical front side band which interconnects the fins and spaces the front shock absorber from the flashlight crown.
The front annular flange and the cylindrical front side band tend to distribute impact forces circumferentially around the flashlight crown so as to reduce localized stresses adjacent the point of first contact between the front of the flashlight and the ground or any other hard impact surface. This cushioning is effective for absorbing both axial and radial impact forces applied to the front shock absorber. An annular resilient rubber or elastomeric cap can be provided between the bottom of the front fins and the top edge of the flashlight crown to further absorb and distribute impact forces around the flashlight crown.
Impact forces received by the fins and circumferentially distributed by the front annular flange and the front side band are further absorbed by the axially-extending ribs which can be molded homogeneously with the front fins, front annular flange and front side band. The ribs can extend radially outwardly from the outer surface of the front side band and extend axially from the front fins to a rear annular or cylindrical band which surrounds and grips a rear portion of the flashlight head portion. The rear band anchors the front shock absorber on the flashlight crown.
With the ribs interconnecting the front and rear bands, forces received by the fins are transferred to the front side band and also to the rear band via the axially-extending ribs to further dissipate shock throughout the front shock absorber. That is, the rear band can circumferentially grip the flashlight body and further distribute forces to a portion of the flashlight axially spaced rearwardly from the front side band.
Because the ribs extend radially outwardly from the flashlight body, they protect the underlying side walls of the flashlight body from the shocks applied radially to the flashlight. The ribs can be dimensioned to either extend in contact with the underlying flashlight body and/or overlie the underlying flashlight body with a small clearance. In one embodiment, a clearance space between the ribs and the flashlight body allows the ribs to flex radially inwardly and absorb shock prior to transferring radial shock forces to the flashlight body.
The rear band is designed to radially grip and clamp around the rear crown portion of a flashlight. This can be achieved by forming the front shock absorber in two generally semi-cylindrical half shells. The half shells can be clamped together with any suitable fasteners such as screws, rivets or with an integrally formed snap fit connection. A tongue and groove connection can also be molded into the contacting surfaces of each half shell to provide an axially-sliding friction connection therebetween. Adhesive bonding can also be used.
Modern high intensity flashlights can generate a significant amount of heat around the flashlight crown which houses one or more incandescent bulbs or one or more light emitting diodes (LEDs). In order to allow for the efficient transfer of heat from the flashlight crown to ambient, the ribs are spaced apart with large open spaces between them to allow direct contact between the flashlight crown and the surrounding ambient air. Such open spaces are not as necessary around the cooler tail end of the flashlight.
The rear shock absorber has a structure similar to the front shock absorber. A series of rear fins projects axially rearwardly from the rear shock absorber to absorb both axial and radial impact forces applied to the tail portion of a flashlight. The rear fins are supported on an end cap formed with a cylindrical side wall and an annular end wall. The end wall extends radially inwardly from the side wall to a central axially-raised circular wall surrounding a circular opening. An elastic or rubber thimble cap serving as a switch cover and switch actuator extends rearwardly through the circular opening from within the end cap for actuating an on-off switch mounted on the tail of the flashlight.
As with the front shock absorber, the rear shock absorber is provided with a series of circumferentially-spaced-apart radially-projecting ribs which extend along the cylindrical side wall of the rear shock absorber. An axial and radial clearance fit can be provided between the end cap and the rear or tail portion of a flashlight. The ribs can extend from the fins as described above.
The rear shock absorber can also be mounted to the tail of a flashlight with a simple friction fit or with a separate locking ring. The locking ring can be formed as a frustoconical or axially tapered band which encircles and radially grips the tail of a flashlight. Axially-extending locking tabs are formed on the locking ring to engage the inner end of the cylindrical side wall of the end cap with one or more snap fit connections. External ribs can be formed on the locking ring to match and align with the ribs on the end cap. Axial and radial clearances can be maintained between the rear shock absorber and the rear portion of the flashlight to provide a “safety zone” similar to that provided around the front portion of the flashlight.